<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"> 
<title>菜鸟教程(runoob.com)</title><!--演示了如何设置字体的加粗-->
<style>
p.normal {font-weight:normal;}/*指定字体的粗细*/
p.light {font-weight:lighter;}
p.thick {font-weight:bold;}
p.thicker {font-weight:900;}
</style>
</head>

<body>
<p class="normal">This is a paragraph.</p>
<p class="light">This is a paragraph.</p>
<p class="thick">This is a paragraph.</p>
<p class="thicker">This is a paragraph.</p>
</body>

</html>